diff --git a/metropolis/node/core/localstorage/crypt/blockdev.go b/metropolis/node/core/localstorage/crypt/blockdev.go
index 099610d..fb55aab 100644
--- a/metropolis/node/core/localstorage/crypt/blockdev.go
+++ b/metropolis/node/core/localstorage/crypt/blockdev.go
@@ -120,6 +120,9 @@
 		// not contain this partition.
 		skipDisk = true
 		for _, part := range table.Partitions {
+			if part.IsUnused() {
+				continue
+			}
 			if part.ID == espUUID {
 				skipDisk = false
 				break
diff --git a/metropolis/node/core/update/e2e/testos/main.go b/metropolis/node/core/update/e2e/testos/main.go
index cba1ade..95f865c 100644
--- a/metropolis/node/core/update/e2e/testos/main.go
+++ b/metropolis/node/core/update/e2e/testos/main.go
@@ -104,6 +104,9 @@
 		Logger: supervisor.MustSubLogger(ctx, "update"),
 	}
 	for pn, p := range vdaParts.Partitions {
+		if p.IsUnused() {
+			continue
+		}
 		switch p.Type {
 		case gpt.PartitionTypeEFISystem:
 			if err := unix.Mount(fmt.Sprintf("/dev/vda%d", pn+1), "/esp", "vfat", unix.MS_SYNC, ""); err != nil {
diff --git a/metropolis/pkg/gpt/gpt.go b/metropolis/pkg/gpt/gpt.go
index f5c2a907..fb011c6 100644
--- a/metropolis/pkg/gpt/gpt.go
+++ b/metropolis/pkg/gpt/gpt.go
@@ -152,7 +152,9 @@
 	BootCode []byte
 
 	// Partitions contains the list of partitions in this table. This is
-	// artificially limited to 128 partitions.
+	// artificially limited to 128 partitions. Holes in the partition list are
+	// represented as nil values. Call IsUnused before checking any other
+	// properties of the partition.
 	Partitions []*Partition
 
 	b blockdev.BlockDev